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JPA Entity Fields

superclasses) can be classified into the following five groups: Transient fields Persistent fields Inverse (Mapped By) fields Primary key (ID) fields Version field The first three groups (transient, persistent ... two groups (primary key and version fields) can only be used in entity classes. Primary key fields

ObjectDB Object Database Features

OUTER JOIN and JOIN FETCH). WHERE (with both JPQL and JDOQL expressions). GROUP BY (including HAVING ... attributes, grouping queries and aggregate queries) which are usually missing from Object Oriented Databases are also supported by ObjectDB. The combination of Object Database features

Paths and Types in JPQL and Criteria API

all these objects (this is an aggregate query with no GROUP BY - all the objects are considered as ... expressions in the above code can be divided into two main groups: FROM variable expressions, represented by ... classes) are represented in JPQL by the following types of expressions: Variables - FROM


entity Since: JPA 2.0 List<Expression<?>> getGroupList() Return a list of the grouping expressions. Return a list of the grouping expressions. Returns empty list if no grouping expressions have been specified. Modifications to the list do not affect the query. Returns: the list of grouping

CRUD Database Operations with JPA

the results (using an ORDER BY clause) and even group results (using GROUP BY and HAVING clauses). JPQL ... a managed entity) by the persist method. The new Point objects are physically stored in the database ... objects in the database by using a simple query: Query q1 = em.createQuery("SELECT COUNT(p) FROM

FROM clause (JPQL / Criteria API)

at the WHERE clause level by using a type expression. For example, in the following query, c iterates ... , and the same query can also be written as follows: SELECT c FROM Country c By default, the name ... name). The default name can be overridden by specifying another name explicitly in the @Entity's


Method javax.jdo.PersistenceManagerFactory void addFetchGroups( FetchGroup... groups ) Add the FetchGroups to the set of active fetch groups. FetchGroups are made unmodifiable before being added ... : groups - an array of FetchGroups Throws: SecurityException - if the caller is not authorized for JDOPermission ("manageMetadata") Since: JDO 2.2


Method javax.jdo.PersistenceManagerFactory void removeFetchGroups( FetchGroup... groups ) Remove the FetchGroups from the set of active FetchGroups. Existing FetchGroups that match parameter ... . Parameters: groups - an array of FetchGroups Throws: SecurityException - if the caller is not authorized for JDOPermission ("manageMetadata") Since: JDO 2.2

[ODB1] Chapter 3 - Persistent Classes

the default fetch group, should not be accessed by this method. void jdoPreStore() Called ... this loaded object that are not in the default fetch group should not be accessed by this method. void ... . Only the state of the object as reflected by its persistent fields is stored. Persistent fields, by default

[ODB1] Chapter 9 - ObjectDB Explorer

Some JVM arguments can be useful. For instance, by default Java does not use more than 64MB ... . Otherwise, the required executable jar would not be found by explorer.exe. By default, running explorer.exe ... Files" menu command. By default, when the Explorer starts its opens the last used local database file

Getting Started

ObjectDB is very easy to use. Follow the Getting Started Tutorial and the Quick Tour manual chapter and in minutes you may be able to write and run first Java programs against ObjectDB.

Prior knowledge or experience in database programming (SQL, JDBC, ORM, JPA, etc.) is not required, but some background in using the Java language is essential.

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